1. Field of the Invention
The present invention concerns a continuous filtration device for filtration of various kinds of liquids to be filtered and, more particularly, it relates to a continuous filtration device which is suitably applied to the filtration of marine fuel oils or lubricants.
2. Description of the Prior Art
Generally, in marine vessels, since fuel oils from an oil tank are filtered in a filtration device and then supplied to an internal combustion engine, filters in the filtration device have to be cleaned periodically or continuously.
By the way, in most of filters for marine vessel fuel oils, a cleaning method by a backwash system that utilizes an inner pressure of a system (4 to 6 kg/cm.sup.2 in a primary system and 10 to 14 kg/cm.sup.2 in a secondary system) has been adopted so far.
Since the conventional filter cleaning method as described above utilizes the inner pressure of the system, there is a problem that a passing rate of a liquid obtainable at the passing surface on the opposite side of the filter is only at such a rate as a backwashing liquid exudes and, accordingly, that no effective regeneration effect can be expected by cleaning.
In view of the above, crews conduct frequent cleaning while opening the filtration device. However, since there are no adequate equipments in the vessel and the cleaning operation has to be completed within a restricted period of time, complete cleaning is difficult even if the crews conduct cleaning by using solvents, steams or high pressure water. Then, there is a problem that the device has to be landed in order to trust regeneration of the device to expert traders or replace it with new one.